clifford et au



Nov. 23, 1948.

n. e. CLIFFORD ETAL v TUNABLE GENERATOR FOR ULTRA HIGH FREQUENCIES FiledDec. 30, 1942 4) 1 1 'mr I) M v INVENTORS ATTORNEY Pat ented Nov. 23,1948 a UNIT-ED STATES iPA l ENT osmos l .TUNABLE ,GENERATORTQRULTRAMIGHt FREQUENCIES v t *Davitl'Grordcn Clifford, Palowlto, cam; arid Ed: 1Ward 'Rawlishen, deceased, *late ofi New'iYork, N .'iY., by: JOhni'P3Wli5h8l'l, =ddministratorj New :York, 'Y.; assignors to:WestinghouseiElectric -i-Corporation,z' :EastPittsbuxgh;rBa;,-ia-wopporationofi Bennsylvania i it t ApplicatioriDecember 30,:1942,"Se'rial'-No."470582 I =9mClaims. (01:: sis-r) Thisinvention relates to ultra-highlfreq-uency slugs-l intoire entrant558215. Cavity :Tesonators devices.andrsgenerators: for.electricityrz'oftultra- ;;;wholly.=-;enclosed'ain vacuum "may -bei't byhigh frequency,Qandmorev particularly tozsuch ztheizmal means, eitherbyvexpansioni50f :aithin 'having' tunable resonant cavities enclosed-winwwal-led pieceibfrtubingsor::bysfilaments ,working evacuated envelopes.N5 sagainsasprings. :Gertainzdifficulties, however; are

.i'llhe principalwobject of thecinvention, generinherentzin-bo'thobthesemethods;although they tally considered, is toprovide;ant-electronic;devtwill. function. .vie comprising anevacuatedenvelope tenclossinconsideringt. the possibility;ofmsingbimetaling acavity resonator associatedwithoth'eneleeliccelementsutor:accomplish:tuning,wit-wasafound mentsforefiecting theidesired -result, said reson-M ve y difficult to obtaina bimetallictstripf a n ator having a; flexible wall,temperature-respon- -two:necessamjqualifications; firstpsufficientwidthsive means in said envelope for adjustin the zxandthiclmesszato:zhavetmechanicalarigidity and position of said --wall1'tottune theresonator;.:means --second,q suflicientw electricala resistivityt 430 give -.a to efiectaheatingJ-dischargex id temperaturevolteamperecharacteristic .in a: range :oonsistent responsive means, andmeans i'orcontrollinglthe i lfi witlnzpractical:application. aA-.filament-;may,tbe intensity of. said discharge in :order to properlycemployed stotheat the bimetallic. strip; :butthermal tune theresonator. i zdelayea-nd'cther disadvantagestmakeethis,unde- Anotherxobject ,-ofthe invention .jiS to; provide s mble.

. for the tuning of resonant cavities in theeevacu- Inaccordancawwiththe =invention,=we-effect the .at d envelopes 0f ultra-high; frequencygener-XQOadesiied tumng-rofta cavity resonator any-evacuators bymeansavoiding timedelay-and possiblity =ated envelope: by mp oy ng b and ofleaks. making it the anode of a small triode. ":Such tri- :A furtherobject of. the invention. is to-provide coda-includes!325011168, fi tsflw ay be a device ior:. generating-electricity.of.ultraehighr.a;filamentlofuanyssuitablex'materialcor an :indifrequency, consistingof an evacuatedaenvelope125 irectlyoheatedlcathode. Betweenthis-sourceand enclosing a main cathode, .a.,cavi ty resonator thebimetalliciielement, tunctioning-as-an anode,

vthrm ghwhich an electronstreamt from; said mainhis:aggridastruotureecontrollingv:the :fiow; ofcelectcathode may pass,bin1eta11ic .mea,ns,fgr,,movjng ,etronsf-rom.thevsource:ofieelectronstorthe bimetala flexible wall of ,saidresonator to tune the c- -e e entsame, and means for efiecting anindeendent, e =13yvirtue:ofthisconstructiom-we 'provideheat- Vaccuratelyecontrollable,,discharge .to: said'. bimeingp wer duetoflelectrontbombardme e y .tallic means to accurately positionsaidflexible lthe de ce w ll respond more rap ly h F 1 wall to eifecttuning.r v Hheatedtbyradiation .fromma. filament andvefiect Other obj ects. andadvantages of the invention, v control; .by'la r negative, grid whichrequires .Jsubrelating to theparticular arrangementcand constantiallmnopower. We? thuswsimplifyccontrol struction of the various partswillbecometapparmircuitsexternaltothetube butwrequiredr-for its entt asthe description proceeds. ..,operation.

Referring tothedraWings illustrating the in- Now referring to thedrawingsin. detail,v.the vention: t reference numeral I lvtdesignates:an. evacuated Fig. 1 .is a fragmentary.axialsectionalview-ch40 envelopemay be-zgenerally cylindrical and an electron device forgenerating.electricityflof l.mddiromanapp p c s s ultra-high frequencyand invol-vingloneoembodi- .The tenvelopelis rigidwthroughoutland ..doesnot ment of the invention. .nedsto have-anylmoving-.parts projectingtthere- Fig. 2 is a fragmentary axial sectional viewon through in orderto embody thevention. ead- .thelineIIII ofjEig. 1,. in. the. directionwofvlthe incon'ductors.orielementsnlZareshownformak- .arrows. lingtthe.desired connections. tTwotof theseele- Fig. 3 is a wiringidiagramiforlthev apparatus ..mentsvconnecttwitmanincandescible,filament 13 of Figs. 1 and 2. I Lfon heatinghan.associatedcathodel4 toelectron- The use of -a cavity. resonatorsastanhintegral-.-emittingwtemperature. Theccathodedhhas its part of. an. electronicclevicev brought about.,cer- 5 ,vupperaors. active isi rface desirablywcoated iwith tain problems. in connection withltuningsuchta electron ir-emission .material, 7 such @25 alkaline resonator .by change of its:physical: dimensions, earths.

when in 'the'evacuated vdevice. tEarlymethods in- The structure whichsurroundsrthevfilament l3 volved the use: of rflexibleldiaphragms.Later, =an dlcathodetl4amaydbe -of:ygeneratlyconventional tuning wasefiectedmby theinsertion. of tmetallice': 55. constructiontand :carried;.by t-thelowereor baseadjacent wall 15 of a cavity resonator l6 whichwall is in turn carried by support members I! and I8, of nickel or otherdesirable material, enclosed in ceramic insulating cylinders I9 and 2|,and carried by a pair of lead-in conductors l2. The upper or oppositewall of the cavity resonator l6, consists of a resilient metal plate 22which may be generally annular in plan and carry concentric corrugations23 for increasing its efiective flexibility. The central portion of theplate 2.2 is connected to a hollow yoke structure 24 which is in turnconnected through a strut 25 to approximately the center of a bimetallicplate 26. One edge of the plate is mounted, as by welding on a channelmember 21, the latter in turn carried by a rigid cross brace 28extending between and supported on the ceramic members I9 and 2 I.

In operation, a beam of electrons is directed axially of the envelopefrom the cathode 14, through a grid 29 carried by the cathode structure,a grid 3! carried by an upstanding or axially ,directed flange definingan opening in the lower wall l of the cavity resonator l6, and a grid 32carried by the upper or flexible wall 22 of the resonator and spanningthe central opening in the yoke structure 24, after which said electronsengage and are reflected back from a member 33. The reflector 33 ismounted on a transverse bracing structure 3A, supported by the ceramicmembers it and 2|. 1

From the above, the construction will be recognized as a hollow bodyresonant micro-wave generator of the reflex type, called a reflexklystron, wherein the upward or forwardly moving electrons are bunchedin passing through the constriction between the grids 3! and 32, givingup'energy while passing back therethrough in bunches on the reflected orreturn path. Tuning of the resonant chamber I6 may, therefore, beobtained by changing .the spacing between the grids 3i and 32 and thedistance between the walls I5 and 22. Y

To make such a change we provide a means for heating the bimetallicelement 26 to cause the same to flex down, or toward themain cathode I4, from the position shown in full lines to that shown in dotted lines,to thereby move the flexible wall 22 and its associated grid 32 closerto the lower or base-adjacent wall I5 defining the cavity resonator 16.Such action lowers the generated frequency, as will be understood bythose skilled in the art. It will also be understood that such devicesmay be constructed so that when the bimetallic element 26 is at roomtemperature, the frequency generated may be a little higherthan thatdesired. The frequency desired may then be produced by heating thebimetallic element 26 to the necessary extent. I

Mounted above the bimetallic element 26, or on the other side from thecathode i4, is a control cathode 35 which may be an incandesciblefilament or indirectly heated electron emissive surface, the ends ofwhich are supported by the insulating cylinders l9 and 2!. In thepresent embodiment we have shown a helical coil 36 surrounding thecathode 35 so as to control the electronic stream between it and thebimetallic element 26. This, however, is not essential, as a griddisposed entirely between the cathode 35 and bimetallic element .26 maybe employed. This grid 36 is shown supported by a wire 3! the ends ofwhichare respectively secured to the insulating cylinders 59 and 2|.

The mode of operating the generator of Figs. 1 and 2 will be apparentfrom the wiring diagram 4 of Fig. 3. The reference character 38represents a transformer, the primary winding 39 of which is suppliedfrom a suitable source of power which .maybe 60 cycle alternatingcurrent. The secon'dary winding 4| supplies power to the cathode heatingfilament l3, as well as by the shunt wires 32 and 43 to the heatingmeans of auxiliary or control cathode 35. The cavity resonatorincludingthe walls 15 and 22 is maintained at a positive potential withrespect to the cathode M, as represented by thebattery 44, while thereflector 33 is made negative with respect to said cathode M, asrepresented. by the battery 45. The bimetallic element 26 is shownmaintained at the same potential as the walls of the resonant chamber I6by electrical connection 46 and the potential of the control grid 36 ismanually variable, being governed by moving a pointer 41 of a rheostator voltage divider t8, the ends of which are connected across a sourceof direct current such as battery 49.

It'will, therefore, be seenthat by making the voltage of the controlgrid 36 more or less negative with respect to the electron-emittingauxiliary cathode 35, the dischargeof electrons therefrom to heat thebimetallic element 26 to the desired temperature, may be accuratelycontrolled. Thus the position of the flexible wall 22 and its associatedgrid 32 may be adjusted to make the frequency of the generatedelectricity that desired,-within the limits allowed by the structure. 1

From the foregoing, it will be seen that there is provided an electrondevice for generating ultrahigh frequency-in which all the essentialparts are. enclosed in an evacuated envelope, even includingthebimetallic means for tuning the resonant-cavity by changingthe'physical dimensions thereof and the spacing'of the grids associatedtherewith. It will be noted that only one extra base pin or terminal isrequired, that is for the grid 36, since the control cathode may beoperated in parallel with the main cathode and the bimetallic elementdirectly connected to the resonant chamber. y

Although a'preferred embodiment of the invention has-been disclosed, itwill be understood that modifications may be made within the spirit andscopeof the appended claims.

Weclaim:

1. An ultra-high frequency generator of the reflex klystron type,comprising an evacuated envelope, a main electron-emissive cathode, acavity resonator through whichsaid cathode may discharge a beam ofelectrons, a reflector electrode at the opposite side of the resonatorfrom said cathode support means for said members, one of the walls ofsaid resonator through which said beam passes being flexible, abimetallic plate with one end rigidly secured to said support means, astructure straddling said reflector electrode and connecting a portionof said bimetallic plate which is spaced from its secured end to theflexible wall, a control cathode disposed adjacent ply source adapted tobe manually varied in poegeaeoa trol cathode and bimetallicplate,-and'by virtue of the corresponding movement ofsai'd element uponchanging its temperature, adjustably position said flexible wall toeffect a desired tuning of said device.

2. An ultra-high frequencydevice comprising a main electron-emissivecathode, a cavity resonator adjacent thereto, bi-metallic means havingone end fixed with respect to the device, allowing the remainder to haveflexing movement to and from said resonator, means connecting a movableportion of said bimetallic means to said resonator, a control cathodedisposed adjacent said bimetallic means, a grid disposed between saidcontrol cathode and said bimetallic means, potential-source meanscoupled to said bimetallic means and control cathode for making saidbimetallic means function as an anode for said controlcatho'de, anenvelope enclosing :all of said elements, connections from said controlcathode to a source of current for efiecting an electron discharge fromsaid control cathode through said grid to said bimetallic means to heatthe same to a desired temperature, a manually-variable electrical supplysource, and connections thereto from said control cathode and grid forregulating the potential of the latter to control said electrondischarge therethrough and the corresponding heat eifect on thebimetallic means to adjustablydistort said cavity resonator and effect adesired tuning.

3. An ultra-high frequency device comprising a main electron-emissivecathode, a cavity resonator adjacent thereto, a wall of said resonatorbeing flexible, bimetallic means having one end fixed with respect tothe device, allowing the remainder to have flexing movement to and fromsaid resonator, means connecting a movable portion of said bimetallicmeans to said flexible wall, a control cathode disposed adjacent saidhimetallic means at a side thereof opposite the main electron-emissivecathode, a grid disposed between said controlcathode and said bimetallicmeans, potential-source means coupled to said bimetallic means andcontrol cathode for making said bimetallic means function as an anodefor said control cathode, an envelope enclosing all of said elements,connections from said control cathode to a source of current foreffecting an electron discharge from said control oath-ode through saidgrid to said bimetallic means to heat the same to a desired temperature,a manually-variable electrical supply source, and connections theretofrom said control cathode and grid for regulating the potential of thelatter to control said electron discharge therethrough and thecorresponding heat effect on the bimetallic means to adjustably positionsaid flexible wall and effect a desired tuning.

4. An ultra-high frequency device comprising an evacuated envelope, amain electron-emissive cathode, a cavity resonator adjacent said cathodein said envelope, said resonator having a flexible wall, a bimetallicplate having one end fixed in said envelope so that upon heating, theremainder will flex toward said resonator, means connecting anintermediate portion of said plate to said flexible wall, a controlcathode in said envelope adjacent said plate and disposed remote fromsaid main cathode, a grid between said control cathode and plate,potentialsource means coupled to said plate and control cathode formaking said plate function as an anode for said control cathode,connections from said control cathode to a source of current foreffecting electron discharge from said control cathode-through said gridto said plate, a manually-variable electrical supply source, andconnectionsthereto from said control cathode and grid for regulating thepotential of the latter to control said electron discharge therethroughand the consequent heating of said bimetallic plate to adjustablyposition said flexible wall and effect a desired tuning.

'5. A discharge device comprising an evacuated envelope enclosing a maincathode, a cavity resonator through which an electron stream from saidmain cathode may pass, one of the Walls of said resonator beingdistortable, bimetallic means operably connected to said distortable"Wall, a control cathode, a grid therefor, potential-source meanscoupled to said bimetallic means and control cathode for making saidbimetallic means function as an anode for said control cathode,connections from said control cathode to a-source of current forefiecting an independent discharge to said bimetallic means to quicklyheat it to a desired extent, a manually-variable electrical supplysource, and connections thereto from said control cathode and grid tocontrol said independent discharge to vary the heating ofthe bimetallicelement and thereby the physical dimensions thereof to accuratelyposition said distortable wall and effect tuning of the resonator.

6. A tuning device for an electron-discharge element through which adischarge may pass from a main electron source in an evacuated envelope,comprising temperature-responsive means enclosed therein and attached tosaid element, a control cathode, a grid therefor, potential-source meanscoupled to said temperature-responsive means and control cathode formaking said temperature-responsive means function as an anode for saidcontrol cathode, connections from said control cathode to a source ofcurrent for effecting an independent electron discharge to saidtemperature-responsive means, a manually-variable electrical supplysource, and connections thereto from said control cathode and grid tovary the heating of the temperature-responsive means and thereby itsphysical dimensions to vary the physical dimensions of said element andeffect a desired tuning.

7. A discharge device comprising an evacuated envelope, a main electronsource therein, and a tuning device for an element through which adischarge may pass from said source, comprising bimetallic meansattached to said element, a control cathode, a grid therefor,potentialsource means coupled to said bimetallic means and controlcathode for making said bimetallic means function as an anode for saidcontrol cathode, connections from said control cathode to a source ofcurrent for effecting an independent electron discharge to saidbimetallic means, a manually-variable electrical supply source, andconnections thereto from said control cathode and grid to vary theheating of said bimetallic means and thereby the physical dimensionsthereof to vary the physical dimensions of said element and effect adesired tuning.

8. An ultra-high frequency device comprising a main electron source, acavity resonator adjacent thereto, temperature-responsivemeans at tachedto said resonator to vary physical dimensions thereof, a control cathodeadjacent said temperature-responsive means, a grid for said controlcathode, potential-source means coupled to said temperature-responsivemeans and control cathode for making said temperature-responsive meansfunction as an anode for said control cathode, an envelope enclosing allof said elements, connections from said control cathode to a source ofcurrent exterior of said envelope for efiecting an electron dischargethrough said grid between said control cathode andtemperature-responsive means, a manuallyvariable electrical supplysource, and connections thereto from said control cathode and grid forregulating the potential of the latter to control the heating effectproduced by said discharge and adjustably distort said resonator toefiect a desired tuning.

9. An ultra-high frequency device comprising a main electron source, acavity resonator adjacent thereto, a wall of said resonator beingflexible, temperature-responsive means connected to said flexible wall,a control cathode disposed adjacent said temperature-responsive meansbut relatively remote from said main electron source, a grid for saidcontrol cathode, potential-source means coupled to saidtemperature-responsive means and control cathode for making saidtemperature-responsive means function as an anode for said controlcathode, an envelope enclosing all of said elements, connections fromsaid control cathode to a source of current exterior of said envelopefor effecting an electron discharge through said gridbetween said control cathode and temperature-responsive means, a manually-variableelectrical supply source, and connections thereto from said controlcathode and grid for regulating the potential of said grid to controlthe heating effect produced by said discharge and adjustably positionsaid flex,- ible wall to effect a desired tuning.

DAVID GORDON CLIFFORD.

JOHN PAWLISHEN, Administrator of the Estate of Edward Pawlz'shen,

-- Deceased.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Great Britain June 25, 1941

